1. Field
The present invention relates generally to the field of optical sensors and switches. More specifically, the present invention relates to optical sensors and switches for demarcating optical networks and isolating network signal fault conditions.
2. Description of the Related Art
In a typical optical network deployment, there is generally a point at which the service provider hands off its high-speed optical fiber to equipment under the control of another entity, such as another service provider or an end-user. This equipment, which is not under the control of the service provider, is often referred to as customer premise equipment (CPE). Because the CPE is not under the control of, and often times not accessible by, the service provider, the obligation of the service provider to ensure network functionality often exists only up to the point where the service provider network interfaces with the CPE.
FIGS. 1a and 1b are block diagrams showing a typical interface 100 between a service provider network and a customer premise network. A network demarcation line 110 generally denotes the boundary between the equipment of the service provider and the CPE. On the left-hand side of the network demarcation line 110 is the service provider equipment, which may include a high-speed optical fiber, such as an OC-X fiber. The CPE is shown on the right side of the network demarcation line 110. Where the CPE is provided for an end-user, the CPE may include a fiber multiplexer 102 that derives multiple DS3 or DS1 signals 108 from an incoming high-speed inbound data signal 106. As noted above, generally and theoretically, the responsibility of the service provider for providing service ends at the network demarcation line 110.
As shown in FIG. 1a, both the high-speed inbound data signal 106 and a valid high-speed outbound data signal 104a directly connect to the CPE multiplexer 102. As a result, a cut output fiber, a disconnected output fiber, or a CPE multiplexer 102 failure may create a loss-of-signal (LOS) that is propagated into the service provider's network. For example, as shown in FIG. 1b, the CPE multiplexer 102 suffers from an equipment failure 112 that results in an LOS condition and an invalid outbound signal 104b. Customers may alert the service provider of the problem or service provider network control equipment may detect the error. However, because there is no intelligence at the network demarcation line 110, the service provider may need to dispatch field technicians to diagnose the entire fiber facility at or near the interface. Once in the field, the technicians may discover that the failure is due to CPE, and is either not responsibility of the service provider or not accessible by the service provider.
In view of the above issues, it would be beneficial to have a system and method for demarcating an optical network, especially one that can generate a loopback condition in each of the networks. Such a system could prevent the propagation of LOS conditions from one network to another, and could promote efficient use of quality control resources, amongst other benefits.